A, that was not a joke,
that was a SINCERE request.
The Big Bang Theory Season 6, Episode 24
Okay. Now, see you look SINCERE
but your words are completely false.
The Big Bang Theory Season 10, Episode 6
...and if I can figure out a way to do so
and sound SINCERE, I will.
The Big Bang Theory Season 4, Episode 9
And I want you to know that
that is SINCERE. I do feel bad.
The Big Bang Theory Season 9, Episode 13
Did you make the apology
as SINCERE as I would have?
The Big Bang Theory Season 9, Episode 23